In conventional scroll expanders, a compression chamber of a compressing means is formed by a first fixed scroll and an orbiting scroll, and at the same time, an expansion chamber of an expanding means is formed by a second fixed scroll and the orbiting scroll. The orbiting scroll is linked to a crankshaft, and is configured so as to be driven to revolve by a motor mounted to the crankshaft (see Patent Literature 1, for example).
Patent Literature 1: Japanese Patent Publication No. HEI 07-037857 (Gazette: pp 3-4; FIG. 1)